1. Technical Field
This invention is related to the field of internal combustion engines having valve train assemblies covered by valve covers. More specifically, this invention relates to two-piece valve covers.
2. Discussion
Valve train assemblies include, amongst other items, valve rocker arms and push rods lubricated with engine oil. In order to maintain the effective and efficient working of such valve train assemblies, such assemblies must remain lubricated and must be protected from debris in the engine compartment. As such, valve train assemblies are usually provided with a cover, more commonly referred to as a valve cover, attached to the engine in order to prevent the loss of engine oil and to protect such assemblies from debris.
The valve covers are attached to the engine with the use of a gasket and various fasteners. The gasket provides for an effective sealing arrangement between the valve cover and the engine head. Some examples of such gaskets are known to be O-ring type gaskets having a circular cross section, flat type gaskets having a rectangular-like cross section, and custom molded gaskets having a variety of cross-sections. In some cases, the gasket is placed on a sealing surface of an engine head with the use of a sealing compound in order to assist in retaining the gasket on the engine head while locating and attaching the valve cover to the engine head and in some cases, mechanical fasteners can accomplish the same purpose. The mechanical fasteners are usually threaded bolts or stud and nut combinations.
To permit the repair of valve train components, the valve covers must be removed in order to provide access to such components. After removing the fasteners retaining the valve cover to the engine head, the valve cover is removed from the engine head to thereby expose the valve train components for inspection, adjustment, and repair. Usually when removing the valve cover, the engine oil found in the cylinder head area can spill out into other areas of the engine compartment and the adjacent floor surface causing a considerable mess. In the case of racing activities involving an engine, the valve train assemblies play an important role in such activities and, as such, the immediate need to remove the valve covers quickly, easily, and neatly becomes important. In such cases, mechanics need to have rapid access to the valve train in order to inspect, adjust, or repair certain components of the valve train.
Prior art valve covers include both one and two-piece valve covers. Such prior art valve covers are typically made by stamping steel or by casting various materials. Usually, the prior art valve covers are heavy or utilize a significant and costly amount of material since a substantial wall and mounting flange thickness is needed to provide for a distortion-resistant and leak-resistant flange to seal the engine reliably or, in the case of a two-piece valve cover, to seal both pieces of the two-piece valve covers together reliably. These heavy and substantial prior art valve covers are time consuming and difficult to assemble to, and remove from, the engine. In addition, prior art valve covers utilize old conventional sealing arrangements which add cost and complexity to the valve covers. Such old conventional sealing arrangements for one and two-piece valve covers are known to include features on the mounting flange (the portion of the cover configured to seal with the engine head) for retaining a gasket to such flange. Such covers having retaining features on the mounting flange require a larger dimension and/or greater wall thickness thereby increasing weight and material consumption. Also, another deficiency of the prior art is the failure to provide for the retention of engine oil upon the removal of the prior art valve covers from the engine head, such failure occurring whether the engine is turned off or operating.